Rubber compound.



JEBOIQIE SMITH, OF CHICAGO, ILLINOIS, ASSIGNOR T ARKON CARBON (30.. OF CHICAGO,

- ILLINOIS, A CORPORATION OF COLORADO.

RUBBER COMPOUND.

lilo Brewing.

Specification of Letters Patent. Patented hint. 15, 1915}.

Application filed May 14, 1909. Serial No. 495,898.

ber applied it rendereddesirable for the purpo byreason of its possessinghesides elasticity, properties which lend to it tensile strength. and render it insulating to heat and electricity and resistant to deterioration under subjection to the influences of the atmosphere, sun-light, acids and alkalies.

The object of my invention is to provide a vulcanizable rubber compound which shall aii'ord to the finished product made from it all the properties specified in an exception- 26 ally high degree; and this I accomplish by employing as an ingredient in the compound the natural product hereinafter described.

have discovered that the hydrocarbon suliastanee known as grahainite, when redUCifCl. to a very finely pulverized condition and used in that condition as an ingredient in a rubber compound, acts as a binder and renders the vulcanized product very high in tensile strength and in heat and electric insu- 3G lating properties, as also highly resistant to the oxidizing tendency of the atmosphereand of sunlight and to the deteriorating action of acids and alkalies. This grahamite, according to The Asphalt aml'Bz't m minous Roc Deposits of the United States,

by George H. Eldridge, Washington, 1901 is one niember of a group of solid asphaltites,

the group containing also alber'tite, impsouite, nigrite and uintahite, each of which is, eh like graharnite, susceptible of itady t-rituration to an iinpslpable powder, and may be used for my purpose as possessing the qualities of grahamite but in lesser degree, so that the latter preferred. y is To produce my iniprovedtcompound, the ahaniite is reduced to a very fine degree of lverization, preferably to about two hundrer mesh, and nixed with other ingredients rdiiu-rrily used in compounding rul'ibcr. l heioliowing formula is one Which I have Jllydsed and which will serve for guidance-to those skilled in the art for practicing my invention.

This mixture is compounded in the usual my and cured ,under subjection to steam-- pressure of (30 lbs. for thirty-five niim'itcs (when cured in a thickness of about one inch in a heavy mold). The vulcanized product possesses the superior qualities hereinbetore statedfnhich are. imparted thereto by the grahzunito asa hinder, the proportion o'l which to the other ingredientsis, according;- to the above formula, half and half, although this proportion may be Varied without departure from my ini n'ovenieiu.

The same formula may be employed for producing an excellent quality of hard rubher by increasing the sulfur ingredient to 25 lbs, curing for 310 minutes under steampressurebeginning at (ll) lbs. and gradually raising it to lbs. and continuing the curing operation under the T5-pound pressure f( a. )(tl'lGfl of ,2 hours; and tlun'ehftei cool.- ing the product for one hour (this direction being based on a thiclmess of the material of about one and one-half inches cured in a heavy iron mold);

)Vhilc .l have. described grinding-the asphall'ile separately and then mixing it in its pulverized condition with the other iugredients of the rubber compound, it is ob vious that it is not necessary to do so, as thcxingi'edients including the asphaltite may all bemixed together with the asphaltite in 0 its original form and the mass ground to-- gethcr.

l'Vh-at I claim as new and desire to secure by Letters Patent is 1. As an ingredient in a completed rubber-compound an asphaltite, as such, in finely pulverized condition, for the pin-pose set forth.

2. As an ingredient in a. rubber-Cozupound, the substance grahamite in a finely puliiprized condition, for the purpose set fort sasphaltite, as such, in a finely pulverized 5. As an ingredient in a completed ber-compound arci frmble bztumen s21 7 m a finely powdered COIldltlOIlg for the pose se; ierth.

JEEEEOME b.

3. A- IUbb8I' -COInp( llI1d co nsisting of a mixture of rubber, sulfur filler mammal and condition.

4:. A rubber compound consisting of a mi xture of rubber, sulfur filler matemal and guhgzrulentfg'ahamite,for the purpose set :mrt

I In presence f- 1 RALPH A. SCHAEFER. Jam: Wxmou. 

